We reviewed 16 patients with spina bifida and unilateral dislocation of the hip at an average age of 17 years. Nine had a high neurological level (thoracic to L3) and seven a low lesion (L4 to sacral). We assessed the influence of unilateral dislocation of the hip on leg-length discrepancy, hip pain, hip stiffness and pressure sores of the ischial tuberosity. In non-walking patients with high-level lesions, unilateral dislocation gave little functional disability and did not appear to require reduction. In walking patients with low-level lesions, leg-length discrepancy led to a poor gait and functional problems which could be prevented by reduction of the dislocation. In all patients with low lesions, surgery was successful in maintaining reduction; in two of five patients with high lesions it was unsuccessful.